Sequential impregnation for noble metal alloy formation

ABSTRACT

Methods are provided for forming noble metal catalysts comprising both platinum and a second Group VIII metal, such as palladium, with improved aromatic saturation activity. Instead of impregnating a catalyst with both platinum and another Group VIII metal at the same time, a sequential impregnation can be used, with the Group VIII metal being impregnated prior to platinum. It has been discovered that by forming a Group VIII metal-impregnated catalyst first, and then impregnating with platinum, the distribution of platinum throughout the catalyst can be improved. The improved distribution of platinum can result in a catalyst with enhanced aromatic saturation activity relative to a catalyst with a similar composition formed by simultaneous impregnation.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Application Ser.No. 62/271,499 filed Dec. 28, 2015, which is herein incorporated byreference in its entirety.

This application is related to a co-pending U.S. application, filed onan even date herewith, and identified by Ser. No. 15/381,549 (entitled“DEWAXING CATALYST WITH IMPROVED AROMATIC SATURATION ACTIVITY”), whichis incorporated herein by reference in its entirety.

FIELD

Methods are provided for impregnation of noble metals on hydroprocessingcatalysts.

BACKGROUND

Platinum is a commonly used metal for hydrogenation and dehydrogenationreactions during catalytic processing of hydrocarbonaceous feeds.Although platinum has a lower resistance to poisoning by sulfur, forsufficiently clean feeds platinum can provide a superior level ofcatalytic activity relative to base metals and/or palladium. In somesituations, alloys of platinum and palladium can be used, in an effortto provide activity similar to platinum while retaining some desirableproperties of palladium. Conventionally, dispersion of platinum on acatalyst is used as an indicator of whether a suitable distribution ofplatinum has been achieved on a catalyst.

U.S. Pat. No. 8,546,286 describes methods for preparing hydrogenationcatalysts. Prior to impregnation of a catalyst with Pt and/or Pd, ananchoring compound is deposited on the catalyst. The anchoring compoundreduces or minimizes the tendency for noble metals deposited on thecatalyst to agglomerate over time.

SUMMARY

In one aspect, a method of making a supported catalyst is provided. Themethod includes impregnating a support comprising at least one of azeolitic support and a mesoporous support with a Group VIII metal salt,such as a palladium salt. The support can be calcined under firsteffective calcining conditions to form a Group VIII metal-impregnatedcatalyst. The Group VIII metal-impregnated catalyst can then beimpregnated with a platinum salt. The Group VIII metal-impregnatedcatalyst can then be calcined under second effective calciningconditions to form a platinum- and Group VIII metal-impregnatedcatalyst. The platinum- and Group VIII metal-impregnated catalyst canhave a combined amount of platinum and Group VIII metal of 0.1 wt %-5.0wt % based on the weight of the supported catalyst. The platinum- andGroup VIII metal-impregnated catalyst can be used, for example, tohydroprocess a feed having an aromatics content of at least 5 wt % toform a hydroprocessed effluent.

In another aspect, a supported catalyst is provided. The supportedcatalyst can include a support comprising at least one of a zeoliticsupport and a mesoporous support. The supported catalyst can furtherinclude 0.1 wt % to 5.0 wt %, based on a weight of the supportedcatalyst, of a combined amount of platinum and Group VIII metal, such aspalladium. A weight ratio of platinum and Group VIII metal can be from0.1 to 10. The supported catalyst can have a catalyst width and anaverage platinum content per volume. A peak platinum content per volumeacross the catalyst width can differ from the average platinum contentper volume by less than 100% of the average platinum content per volume.The supported catalyst can be used, for example, to hydroprocess a feedhaving an aromatics content of at least 5 wt % to form a hydroprocessedeffluent.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 shows results from performing aromatic saturation of a feed usinga co-impregnated Pt—Pd catalyst and a sequentially impregnated Pt—Pdcatalyst.

FIG. 2 shows metal content per volume across the catalyst width for aPt—Pd catalyst formed using co-impregnation.

FIG. 3 shows metal content per volume across the catalyst width for aPt—Pd catalyst formed using sequential impregnation.

FIG. 4 schematically shows a reaction configuration for hydroprocessingof unconverted oil.

FIG. 5 schematically shows a reaction configuration for hydroprocessingof unconverted oil.

FIG. 6 schematically shows another reaction configuration forhydroprocessing for production of fuels and lubricant base oils.

DETAILED DESCRIPTION

All numerical values within the detailed description and the claimsherein are modified by “about” or “approximately” the indicated value,and take into account experimental error and variations that would beexpected by a person having ordinary skill in the art.

In various aspects, methods are provided for forming noble metalcatalysts comprising both platinum and palladium with improved aromaticsaturation activity. Instead of impregnating a catalyst with bothplatinum and palladium at the same time, a sequential impregnation canbe used, with palladium being impregnated prior to platinum. It has beendiscovered that by forming a palladium-impregnated catalyst first, andthen impregnating with platinum, the distribution of platinum throughoutthe catalyst can be improved. More generally, other Group VIII metals(including non-noble metals) such as Ni, Rh, Ir, Ru, and Co could alsobe used for an initial impregnation to improve the subsequentdistribution of platinum. The improved distribution of platinum canresult in a catalyst with enhanced aromatic saturation activity relativeto a catalyst with a similar composition formed by simultaneousimpregnation. Platinum and palladium catalysts (and more generally otherGroup VIII metal plus platinum catalysts) with improved platinum metaldistribution are also described herein.

Impregnation, such as impregnation by incipient wetness or ion exchangein solution, is a commonly used technique for introducing metals into acatalyst that includes a support, such as a zeolitic support and/or amesoporous support. The total acidity of the support (Bronsted andLewis) affects the dispersion of metals during impregnation byexchanging with the metal precursors. When performing incipient wetnessimpregnation onto a sufficiently acidic material, such as a zeolite, themetal can often “rim” or deposit primarily on the outside of the shapedextrudate or pores. The rimming of the metal is an inefficient use ofmetal, as it can limit the metal available throughout the remainingportions of the catalyst. For reactions such as aromatic saturation ordewaxing, the activity of the catalyst can be dependent on the activityof the catalyst throughout the catalyst support. During impregnation, asupport is exposed to a solution containing a salt of the metal forimpregnation. There are many variables that can affect the dispersion ofthe metal salt during impregnation, including the concentration of thesalt, the pH of the salt solution, the point of zero charge of thesupport material, but not excluding other variables that may also beimportant during incipient wetness or ion exchange impregnation.Multiple exposure steps can optionally be performed to achieve a desiredmetals loading on a catalyst. After impregnating a support with a metalsalt, the support can be calcined under effective calcination conditionsto convert the metal salt to a metal oxide. For example, the support canbe calcined in an atmosphere containing 5 vol % to 30 vol % O₂ at atemperature of 500° F. (260° C.) to 800° F. (427° C.) for 0.5 hours to24 hours. Optionally, the support can be dried at a lower temperaturefor a period of time prior to calcination so that water from theimpregnation solution can be removed prior to starting the calcinationprocedure.

One convenient way of characterizing the acidity of a catalyst is usingthe Alpha value test. The alpha value test is a measure of the crackingactivity of a catalyst and is described in U.S. Pat. No. 3,354,078 andin the Journal of Catalysis, Vol. 4, p. 527 (1965); Vol. 6, p. 278(1966); and Vol. 61, p. 395 (1980), each incorporated herein byreference as to that description. The experimental conditions of thetest used herein include a constant temperature of 538° C. and avariable flow rate as described in detail in the Journal of Catalysis,Vol. 61, p. 395. In various aspects, the sequential impregnationdescribed herein can be used for a support having an Alpha value of atleast 100, or at least 200, or at least 250, or at least 300, or atleast 350, or at least 400.

Typically impregnation can occur after extrusion of a zeolitic and/ormesoporous catalyst. If the catalyst includes a binder, the zeoliticand/or mesoporous catalyst component can be combined with the binder andthen extruded.

Currently, platinum catalysts, palladium catalysts, and catalystsincluding both platinum and palladium catalysts are used for varioustypes of catalyst processing, including hydrocracking, catalyticdewaxing, and hydrofinishing. Catalysts including both platinum andpalladium can be synthesized by co-impregnation of platinum andpalladium complexes onto a catalytic support. The catalyst is then driedto remove water and the complexes are decomposed (i.e., via calcination)in air to produce dispersed platinum and palladium oxides on thesurface.

Conventionally, the effectiveness of a metal impregnation can bemeasured by determining the dispersion of metals on the surface. Anexample of a technique for measuring catalyst dispersion is oxygenchemisorption. During an oxygen chemisorption test, a Langmuiradsorption model is used to identify a distinction between chemisorptionand physisorption of oxygen on the metal surface. The amount of oxygenadsorbed by chemisorption is then compared with an expected amount ofsurface adsorption sites (such as surface metal atoms) to determine adispersion value.

It has been discovered that dispersion (such as dispersion measured byoxygen chemisorption) does not correlate well with aromatic saturationactivity for catalysts including Pt as a hydrogenation metal. Withoutbeing bound by any particular theory, it is believed that dispersionmeasurements provide an indication of distribution of metals on thesurface of a catalyst. However, for many types of molecular sievesand/or porous amorphous catalysts, a substantial portion of the catalystactivity can be based on activity within the pores of the catalyst.Distribution of metals across the width of a catalyst is believed to notbe strongly correlated with the values generated by dispersionmeasurements. Instead, it has been determined that an improvedunderstanding of the activity of a catalyst can be gained by performingenergy dispersive x-ray spectroscopy (EDS) analysis using a scanningelectron microscope (SEM) to characterize the distribution of metalcontent (either Pt or combined Pt and Pd) across the width of acatalyst.

As further detailed in the Examples below, it has been determined usingEDS that when platinum and palladium are co-impregnated, the platinum(and optionally the palladium) may preferentially adsorb on the outsideof a mesoporous or zeolitc support and segregate. This can result in alower concentrations of platinum (and optionally palladium) within thepore structure of the catalyst. This preferential adsorption of platinum(and optionally palladium) at the surface of a mesoporous support,zeolitic support, and/or other type of molecular sieve support can leadto a catalyst with lower aromatic saturation activity.

To overcome this difficulty, it has been discovered that sequentialimpregnation can improve the distribution of metals across the width(i.e., within the interior) of a catalyst. During sequentialimpregnation, at least a portion of the palladium salt(s) impregnated onthe support can be decomposed (such as by calcination) prior toimpregnation of at least a portion of the platinum salts on the support.Performing a sequential impregnation where palladium is impregnatedfirst, and then platinum is impregnated on the palladium-containingcatalyst, can result in improved distribution of platinum (andoptionally palladium) across the width of a catalyst. This improveddistribution is believed to lead to additional formation of higheractivity alloys of platinum and palladium.

The improved distribution of platinum (and optionally palladium) acrossthe width of a catalyst can result in improved aromatic saturationactivity for catalysts including platinum and palladium. This caninclude improved aromatic saturation activity for aromatic saturationcatalysts, dewaxing catalysts, hydrocracking catalysts, and/or any othertype of catalyst used for processing of aromatic containing feeds in anenvironment where hydrogen is present.

In this discussion, the distribution of platinum and palladium acrossthe width of a catalyst can be characterized based on the metal contentper volume of the catalyst across the width. The metal content pervolume for a catalyst can be determined across the width of the catalystusing EDS analysis. For example, after forming a catalyst, the catalystcan be cut and half and a line scan can be performed across the width ofthe cut surface of the catalyst.

An example of EDS characterization of two catalysts is shown in FIGS. 2and 3. In FIGS. 2 and 3, the metal content of the catalyst is normalizedso that the maximum metal content per volume has a value of 1. As shownin FIGS. 2 and 3, the metal content per volume across a catalyst widthcan vary as a function of width. The metal content per volume across thewidth of a catalyst can then be compared with the average metal contentper volume, such as by comparing a peak metal content relative to theaverage metal content. A peak metal content is defined herein as eithera maximum metal content or a minimum metal content for the metal contentper volume across the width of the catalyst. (For FIGS. 2 and 3, basedon the normalization used for the data, the peak metal contentcorresponds to a value of “1” by definition.) The average metal contentper volume can be determined in any convenient manner for determining anumber average based on the metal content per volume across the width ofa catalyst.

In some aspects, a peak metal content per volume and an average metalcontent per volume can be determined for platinum on the catalyst. Insuch aspects, for a catalyst formed by sequential impregnation asdescribed herein, the peak platinum content per volume across the widthof a catalyst can differ from the average platinum content per volumefor the catalyst by less than 200% of the average platinum content pervolume, or less than 100%, or less than 75%, or less than 50%. It isnoted that a peak platinum content that varies by more than 100%relative to the average platinum content per volume can necessarilycorrespond to a maximum peak. For variations of less than 100%, a peakplatinum content can correspond to either a minimum peak or a maximumpeak for the platinum content per volume relative to the averageplatinum content per volume.

In other aspects, a peak metal content per volume and an average metalcontent per volume can be determined for a combined amount of platinumand palladium on the catalyst. In such aspects, for a catalyst formed bysequential impregnation as described herein, the peak metal content(combined platinum and palladium) per volume across the width of acatalyst can differ from the average metal content (combined platinumand palladium) per volume for the catalyst by less than 200% of theaverage metal content per volume, or less than 100%, or less than 75%,or less than 50%.

More generally, a zeolitic catalyst, mesoporous catalyst, and/or othertype of molecular sieve-based catalyst that includes platinum andpalladium as catalytic metals can be used to catalyze a wide variety oforganic compound conversion processes including many of presentcommercial/industrial importance. Examples of chemical conversionprocesses effectively catalyzed by the crystalline material of thisdisclosure, by itself or in combination with one or more othercatalytically active substances including other crystalline catalysts,can include those requiring a catalyst with acid activity. Specificexamples can include, but are not limited to:

(a) alkylation of aromatics with short chain (C₂-C₆) olefins, e.g.,alkylation of ethylene or propylene with benzene to produce ethylbenzeneor cumene respectively, in the gas or liquid phase, with reactionconditions optionally including one or more of a temperature from about10° C. to about 250° C., a pressure from about 0 psig to about 500 psig(about 3.5 MPag), a total weight hourly space velocity (WHSV) from about0.5 hr⁻¹ to about 100 hr⁻¹, and an aromatic/olefin mole ratio from about0.1 to about 50;

(b) alkylation of aromatics with long chain (C.sub.10-C.sub.20) olefins,in the gas or liquid phase, with reaction conditions optionallyincluding one or more of a temperature from about 250° C. to about 500°C., a pressure from about 0 psig to 500 psi, (about 3.5 MPag), a totalWHSV from about 0.5 hr⁻¹ to about 50 hr⁻¹, and an aromatic/olefin moleratio from about 1 to about 50;

(c) transalkylation of aromatics, in gas or liquid phase, e.g.,transalkylation of polyethylbenzenes and/or polyisopropylbenzenes withbenzene to produce ethylbenzene and/or cumene respectively, withreaction conditions optionally including one or more of a temperaturefrom about 100° C. to about 500° C., a pressure from about 1 psig (about7 kPag) to about 500 psig (about 3.5 MPag), and a WHSV from about 1 hr⁻¹to about 10,000 hr⁻¹;

(d) disproportionation of alkylaromatics, e.g., disproportionation oftoluene to produce xylenes, with reaction conditions optionallyincluding one or more of a temperature from about 200° C. to about 760°C., a pressure from about 1 atm (about 0 psig) to about 60 atm (about5.9 MPag), a WHSV from about 0.1 hr⁻¹ to about 20 hr⁻¹, and ahydrogen/hydrocarbon mole ratio from 0 (no added hydrogen) to about 50;

(e) dealkylation of alkylaromatics, e.g., deethylation of ethylbenzene,with reaction conditions optionally including one or more of atemperature from about 200° C. to about 760° C., a pressure from about 1atm (about 0 psig) to about 60 atm (about 5.9 MPag), a WHSV from about0.1 hr⁻¹ to about 20 hr⁻¹, and a hydrogen to hydrocarbon mole ratio from0 (no added hydrogen) to about 50;

(f) isomerization of alkylaromatics, such as xylenes, with reactionconditions optionally including one or more of a temperature from about200° C. to about 540° C., a pressure from about 100 kPaa to about 7MPaa, a WHSV from about 0.1 hr⁻¹ to about 50 hr⁻¹, and ahydrogen/hydrocarbon mole ratio from 0 (no added hydrogen) to about 10;

(g) reaction of paraffins with aromatics, e.g., to form alkylaromaticsand light gases, with reaction conditions optionally including one ormore of a temperature from about 260° C. to about 375° C., a pressurefrom about 0 psig to about 1000 psig (about 6.9 MPag), a WHSV from about0.5 hr⁻¹ to about 10 hr⁻¹, and a hydrogen/hydrocarbon mole ratio from 0(no added hydrogen) to about 10;

(h) paraffin isomerization to provide branched paraffins with reactionconditions optionally including one or more of a temperature from about200° C. to about 315° C., a pressure from about 100 psig (about 690kPag) to about 1000 psig (about 6.9 MPag), a WHSV from about 0.5 hr⁻¹ toabout 10 hr⁻¹, and a hydrogen to hydrocarbon mole ratio from about 0.5to about 10;

(i) alkylation of iso-paraffins, such as isobutane, with olefins, withreaction conditions optionally including one or more of a temperaturefrom about −20° C. to about 350° C., a pressure from about 0 psig toabout 700 psig (about 4.9 MPag), and a total olefin WHSV from about 0.02hr⁻¹ to about 10 hr⁻¹;

(j) dewaxing of paraffinic feeds with reaction conditions optionallyincluding one or more of a temperature from about 200° C. to about 450°C., a pressure from about 0 psig to about 1000 psig (about 6.9 MPag), aWHSV from about 0.2 hr⁻¹ to about 10 hr⁻¹, and a hydrogen/hydrocarbonmole ratio from about 0.5 to about 10;

(k) cracking of hydrocarbons with reaction conditions optionallyincluding one or more of a temperature from about 300° C. to about 700°C., a pressure from about 0.1 atm (about 10 kPag) to about 30 atm (about3 MPag), and a WHSV from about 0.1 hr⁻¹ to about 20 hr⁻¹;

(l) isomerization of olefins with reaction conditions optionallyincluding one or more of a temperature from about 250° C. to about 750°C., an olefin partial pressure from about 30 kPa to about 300 kPa, and aWHSV from about 0.5 hr⁻¹ to about 500 hr⁻¹; and

(m) a hydrocarbon trap (e.g., pre-catalytic converter adsorbent) forcold start emissions in motor vehicles.

In this discussion, a “zeolitic” catalyst is defined as a catalyst thatincludes a framework structure geometry that corresponds to a knownframework type. Examples of known frameworks are those frameworksdocumented in the database of zeolite structures by the InternationalZeolite Association. A zeolite, which is a type of zeolitic catalyst,can have a framework structure that is substantially composed ofsilicon, aluminum, and oxygen. For zeolitic catalysts that are notzeolites, other heteroatoms may form part of the framework structure,including structures where silicon and/or aluminum are entirely replacedwithin the framework structure. Other types of know zeolitic catalystsinclude, but are not limited to, silicoaluminophosphates (SAPOs);aluminophosphates (AlPOs); and/or other catalysts having a zeoliteframework structure where a portion of the silicon and/or aluminum atomsin the framework are replaced with other elements, such elementsincluding but not being limited to titanium, gallium, phosphorous,germanium, tin, boron, antimony, and zinc.

Processing Conditions—Aromatic Saturation

In some aspects, catalysts that can benefit from improved aromaticsaturation activity can include hydroprocessing catalysts, such asaromatic saturation catalysts (sometimes referred to as hydrofinishingcatalysts), dewaxing catalysts, and hydrocracking catalysts.

Aromatic saturation can be performed at various locations within ahydroprocessing reaction system. For example, aromatic saturation can beperformed prior to other hydroprocessing steps, after a sequence ofhydroprocessing steps, or as an intermediate process in a sequence ofhydroprocessing steps.

Suitable aromatic saturation catalysts can correspond to catalystscontaining a combination of Pt and Pd, with Pd being added first bysequential impregnation. Some examples of mesoporous support materialsfor hydrofinishing catalysts can include crystalline materials belongingto the M41S class or family of catalysts. The M41S family of catalystsare mesoporous materials having high silica content. Examples includeMCM-41, MCM-48 and MCM-50. A preferred member of this class is MCM-41.Other suitable mesoporous materials can include, but are not limited to,amorphous metal oxide supports such as silica, alumina, silica-aluminas,titanic, silica-titania, alumina-titanic, zirconia, silica-zirconia,titania-zirconia, ceria, tungsten oxide, and combinations thereof. Insome aspects an amorphous support can be composed of alumina. Thesupport materials may also be modified, such as by halogenation, or inparticular fluorination. The combined amount of Pt and Pd on thecatalyst can be 0.1 wt % to 2.0 wt % based on the weight of thecatalyst, such as 0.1 wt % to 1.8 wt %, or 0.1 wt % to 1.5 wt %, or 0.1wt % to 1.2 wt %, or 0.1 wt % to 0.9 wt %, or 0.3 wt % to 1.8 wt %, or0.3 wt % to 1.5 wt %, or 0.3 wt % to 1.2 wt %, or 0.3 wt % to 0.9 wt %,or 0.6 wt % to 1.8 wt %, or 0.6 wt % to 1.5 wt %, or 0.6 wt % to 1.2 wt%. The Pt and Pd can be included in any convenient weight ratio, such asa Pt to Pd weight ratio of 0.1 (i.e., 1 part Pt to 10 parts Pd) to 10.0(i.e., 10 parts Pt to 1 part Pd). For example, the Pt to Pd ratio can be0.1 to 10.0, or 0.1 to 5.0, or 0.1 to 4.0, or 0.1 to 3.0, or 0.1 to 2.0,or 0.1 to 1.5, or 0.1 to 1.0, or 0.2 to 10.0, or 0.2 to 5.0, or 0.2 to4.0, or 0.2 to 3.0, or 0.2 to 2.0, or 0.2 to 1.5, or 0.2 to 1.0, or 0.2to 0.5, or 0.3 to 10.0, or 0.3 to 5.0, or 0.3 to 4.0, or 0.3 to 3.0, or0.3 to 2.0, or 0.3 to 1.5, or 0.3 to 1.0, or 0.3 to 0.5, or 0.5 to 10.0,or 0.5 to 5.0, or 0.5 to 4.0, or 0.5 to 3.0, or 0.5 to 2.0, or 0.5 to1.5, or 0.5 to 1.0. In some preferred aspects, the weight ratio of Pt toPd can be 0.2 to 1.5, or 0.3 to 1.5, or 0.2 to 1.0, or 0.3 to 1.0.Optionally, other metals can also be present on the catalyst.

Aromatic saturation conditions can include temperatures from about 125°C. to about 425° C., preferably about 180° C. to about 280° C., totalpressures from about 300 psig (2.1 MPa) to about 3000 psig (20.7 MPa),preferably about 1000 psig (6.9 MPa) to about 2500 psig (17.2 MPa),liquid hourly space velocities from about 0.1 hr⁻¹ to about 30 hr⁻¹LHSV, or about 0.5 hr⁻¹ to about 30 hr⁻¹, or about 0.5 hr⁻¹ to about 20hr⁻¹, or about 1.0 hr⁻¹ to about 20 hr⁻¹, preferably about 1.0 hr⁻¹ toabout 15 hr⁻¹, about 1.5 hr⁻¹ to about 15 hr⁻¹, or about 1.0 hr⁻¹ toabout 10 hr⁻¹, or about 1.5 hr⁻¹ to about 10 hr⁻¹, or about 2.0 hr⁻¹ toabout 20 hr⁻¹, or about 2.0 hr⁻¹ to about 15 hr⁻¹, and treat gas ratesof from 35.6 m³/m³ to 1781 m³/m³ (200 SCF/B to 10,000 SCF/B), preferably213 m³/m³ to about 1068 m³/m³ (1200 SCF/B to 6000 SCF/B) of ahydrogen-containing treat gas. The hydrogen-containing treat gas cancontain at least about 80 vol % Hz, or at least about 90 vol %, or atleast about 95 vol %, or at least about 98 vol %.

The aromatic saturation conditions can be effective for reducing thearomatics content of a feed. In various aspects, a feed can be ahydrocarbonaceous feed that includes at least 50 wt % (or at least 75 wt% or at least 90 wt %) of hydrocarbon compounds and/or hydrocarbon-likecompounds that may also include one or more heteroatoms, such as sulfur,oxygen, and/or nitrogen. A feed to an aromatics saturation step (and/ordewaxing and/or hydrocracking) can have an aromatics content of at least5 wt %, or at least 10 wt %, or at least 15 wt %, or at least 20 wt % orat least 25 wt %, or at least 30 wt %, or at least 40 wt %, or at least50 wt %, or at least 60 wt %, such as up to 80 wt % or more. The sulfurcontent can be, for example, 1000 wppm or less, or 5000 wppm or less, or100 wppm or less, or 50 wppm or less. The boiling range of the feed canbe any convenient boiling range, such as a naphtha boiling range feed, adistillate boiling range feed, a gas oil boiling range feed, a stillhigher boiling range feed, or a combination thereof. In this discussion,the distillate boiling range is defined as 350° F. (177° C.) to 700° F.(371° C.). With regard to other boiling ranges, the gas oil boilingrange is defined as 700° F. (371° C.) to 1100° F. (593° C.) and thenaphtha boiling range is defined as 100° F. (37° C.) to 350° F. (177°C.). Optionally, at least a portion of the feed can be derived from abiological source.

In some aspects, the amount of aromatics in the effluent from anaromatics saturation step can be characterized based on a weight percentof aromatics in the effluent. The aromatics content after aromaticssaturation (and/or dewaxing and/or hydrocracking) can be dependent onthe initial amount of aromatics in the feed, and can generally be lessthan 50 wt %, or less than 40 wt %, or less than 30 wt %, or less than20 wt %, or less than 10 wt %, or less than 7.5 wt %, or less than 5 wt%, or less than 3 wt %. In other aspects, the amount of aromatics in theeffluent can be characterized relative to the amount of aromatics in thefeed to the aromatics saturation step. For example, a ratio of aromaticsin the effluent from aromatics saturation to aromatics in the feed canbe 0.6 or less, or 0.5 or less, or 0.4 or less, or 0.3 or less, or 0.2or less, or 0.15 or less, or 0.1 or less.

Processing Conditions—Catalytic Dewaxing

Another type of catalyst that can benefit from improved aromaticsaturation activity is a dewaxing catalyst that includes both platinumand palladium. For example, dewaxing catalysts can be used as part of ahydroprocessing sequence for formation of distillate fuels and/orlubricant base oils. Distillate fuel products and lubricant base oilproducts can, in some aspects, benefit from lower aromatics contents. Adewaxing catalyst with improved aromatic saturation activity can reduceor minimize the severity required in a subsequent aromatic saturation(or other hydroprocessing) stage and/or can potentially eliminate theneed for a subsequent aromatic saturation stage.

Suitable dewaxing catalysts can include molecular sieves such ascrystalline aluminosilicates (zeolites) and other zeolitic molecularsieve structures. In an embodiment, the molecular sieve can comprise,consist essentially of, or be ZSM-5, ZSM-22, ZSM-23, ZSM-35, ZSM-48,zeolite Beta, ZSM-57, or a combination thereof, for example ZSM-23and/or ZSM-48, or ZSM-48 and/or zeolite Beta. Optionally but preferably,molecular sieves that are selective for dewaxing by isomerization asopposed to cracking can be used, such as ZSM-48, zeolite Beta, ZSM-23,or a combination thereof. Additionally or alternately, the molecularsieve can comprise, consist essentially of, or be a 10-member ring 1-Dmolecular sieve. Examples include EU-1, ZSM-35 (or ferrierite), ZSM-11,ZSM-57, NU-87, SAPO-11, ZSM-48, ZSM-23, and ZSM-22. Preferred materialsare EU-2, EU-11, ZBM-30, ZSM-48, or ZSM-23. ZSM-48 is most preferred.Note that a zeolite having the ZSM-23 structure with a silica to aluminaratio of from about 20:1 to about 40:1 can sometimes be referred to asSSZ-32. Other molecular sieves that are isostructural with the abovematerials include Theta-1, NU-10, EU-13, KZ-1, and NU-23. Optionally butpreferably, the dewaxing catalyst can include a binder for the molecularsieve, such as alumina, titania, silica, silica-alumina, zirconia, or acombination thereof, for example alumina and/or titania or silica and/orzirconia and/or titania.

Preferably, the dewaxing catalysts used in processes according to thedisclosure are catalysts with a low ratio of silica to alumina. Forexample, for ZSM-48, the ratio of silica to alumina in the zeolite canbe less than 200:1, or less than 110:1, or less than 100:1, or less than90:1, or less than 80:1. In various embodiments, the ratio of silica toalumina can be from 30:1 to 200:1, 60:1 to 110:1, or 70:1 to 100:1.

In various aspects, a dewaxing catalyst can also include platinum andpalladium as a metal hydrogenation component. The amount of combined Ptand Pd on the catalyst can be from 0.1 wt % to 5 wt %, preferably from0.1 wt % to 2.0 wt %, or 0.2 wt % to 1.8 wt %, or 0.4 wt % to 1.5 wt %.More generally, the amount of combined Pt and Pd on the catalyst can be0.1 wt % to 2.0 wt %, or 0.1 wt % to 1.8 wt %, or 0.1 wt % to 1.5 wt %,or 0.1 wt % to 1.2 wt %, or 0.2 wt % to 2.0 wt %, or 0.2 wt % to 1.8 wt%, or 0.2 wt % to 1.5 wt %, or 0.2 wt % to 1.2 wt %, or 0.4 wt % to 2.0wt %, or 0.4 wt % to 1.8 wt %, or 0.4 wt % to 1.5 wt %, or 0.4 wt % to1.2 wt %, or 0.6 wt % to 2.0 wt %, or 0.6 wt % to 1.8 wt %, or 0.6 wt %to 1.5 wt %, or 0.6 wt % to 1.2 wt %. The Pt and Pd can be included inany convenient weight ratio, such as a Pt to Pd weight ratio of 0.1(i.e., 1 part Pt to 10 parts Pd) to 10.0 (i.e., 10 parts Pt to 1 partPd). For example, the Pt to Pd ratio can be 0.1 to 10.0, or 0.1 to 5.0,or 0.1 to 4.0, or 0.1 to 3.0, or 0.1 to 2.0, or 0.1 to 1.5, or 0.1 to1.0, or 0.2 to 10.0, or 0.2 to 5.0, or 0.2 to 4.0, or 0.2 to 3.0, or 0.2to 2.0, or 0.2 to 1.5, or 0.2 to 1.0, or 0.2 to 0.5, or 0.3 to 10.0, or0.3 to 5.0, or 0.3 to 4.0, or 0.3 to 3.0, or 0.3 to 2.0, or 0.3 to 1.5,or 0.3 to 1.0, or 0.3 to 0.5, or 0.5 to 10.0, or 0.5 to 5.0, or 0.5 to4.0, or 0.5 to 3.0, or 0.5 to 2.0, or 0.5 to 1.5, or 0.5 to 1.0. In somepreferred aspects, the weight ratio of Pt to Pd can be 0.2 to 1.5, or0.3 to 1.5, or 0.2 to 1.0, or 0.3 to 1.0. Optionally, other metals canalso be present on the catalyst.

Process conditions in a catalytic dewaxing zone can include atemperature of about 200° C. to about 450° C., preferably about 270° C.to about 400° C., a hydrogen partial pressure of about 1.8 MPag to about34.6 MPag (250 psig to 5000 psig), preferably about 4.8 MPag to about20.8 MPag, and a hydrogen treat gas rate of about 35.6 m³/m³ (200 SCF/B)to about 1781 m³/m³ (10,000 scf/B), preferably about 178 m³/m³ (1000SCF/B) to about 890.6 m³/m³ (5000 SCF/B). In still other embodiments,the conditions can include temperatures in the range of about 600° F.(343° C.) to about 815° F. (435° C.), hydrogen partial pressures of fromabout 500 psig to about 3000 psig (3.5 MPag-20.9 MPag), and hydrogentreat gas rates of from about 213 m³/m³ to about 1068 m³/m³ (1200 SCF.The LHSV can be from about 0.1 to about 10 h⁻¹, such as from about 0.5h⁻¹ to about 5 and/or from about 1 to about 4 h⁻¹.

Processing Conditions—Hydrocracking in Sweet Operation

Hydrocracking processes are still another type of process that canbenefit from a catalyst including both platinum and palladium that hasimproved aromatic saturation activity. Generally, hydrocrackingcatalysts including platinum and palladium can correspond to catalystsused during a “sweet” hydrocracking stage, where the sulfur content of afeed to the hydrocracking process is 1000 wppm or less, or 500 wppm orless, or 100 wppm or less, or 50 wppm or less.

Hydrocracking catalysts typically contain metals, such as platinum andpalladium, on acidic supports. Examples of acidic supports includecracking zeolites and/or other cracking molecular sieves such as USY,amorphous silica alumina, or acidified alumina. In some preferredaspects, a hydrocracking catalyst can include at least one molecularsieve, such as a zeolite. Often these acidic supports are mixed or boundwith other metal oxides such as alumina, titania or silica. Supportmaterials which may be used can comprise a refractory oxide materialsuch as alumina, silica, alumina-silica, kieselguhr, diatomaceous earth,magnesia, zirconia, or combinations thereof, with alumina, silica,alumina-silica being the most common (and preferred, in one embodiment).

The combined amount of supported Pt and Pd on the catalyst can be 0.1 wt% to 2.0 wt % based on the weight of the catalyst, such as 0.1 wt % to1.8 wt %, or 0.1 wt % to 1.5 wt %, or 0.1 wt % to 1.2 wt %, or 0.1 wt %to 0.9 wt %, or 0.3 wt % to 1.8 wt %, or 0.3 wt % to 1.5 wt %, or 0.3 wt% to 1.2 wt %, or 0.3 wt % to 0.9 wt %, or 0.6 wt % to 1.8 wt %, or 0.6wt % to 1.5 wt %, or 0.6 wt % to 1.2 wt %. The Pt and Pd can be includedin any convenient weight ratio, such as a Pt to Pd weight ratio of 0.1(i.e., 1 part Pt to 10 parts Pd) to 10.0 (i.e., 10 parts Pt to 1 partPd). For example, the Pt to Pd ratio can be 0.1 to 10.0, or 0.1 to 5.0,or 0.1 to 4.0, or 0.1 to 3.0, or 0.1 to 2.0, or 0.1 to 1.5, or 0.1 to1.0, or 0.2 to 10.0, or 0.2 to 5.0, or 0.2 to 4.0, or 0.2 to 3.0, or 0.2to 2.0, or 0.2 to 1.5, or 0.2 to 1.0, or 0.2 to 0.5, or 0.3 to 10.0, or0.3 to 5.0, or 0.3 to 4.0, or 0.3 to 3.0, or 0.3 to 2.0, or 0.3 to 1.5,or 0.3 to 1.0, or 0.3 to 0.5, or 0.5 to 10.0, or 0.5 to 5.0, or 0.5 to4.0, or 0.5 to 3.0, or 0.5 to 2.0, or 0.5 to 1.5, or 0.5 to 1.0. In somepreferred aspects, the weight ratio of Pt to Pd can be 0.2 to 1.5, or0.3 to 1.5, or 0.2 to 1.0, or 0.3 to 1.0.

In some aspects, a hydrocracking catalyst can include a large poremolecular sieve that is selective for cracking of branched hydrocarbonsand/or cyclic hydrocarbons. Zeolite Y, such as ultrastable zeolite Y(USY) is an example of a zeolite molecular sieve that is selective forcracking of branched hydrocarbons and cyclic hydrocarbons. Depending onthe aspect, the silica to alumina ratio in a USY zeolite can be at leastabout 10, such as at least about 15, or at least about 25, or at leastabout 50, or at least about 100. Depending on the aspect, the unit cellsize for a USY zeolite can be about 24.50 Angstroms or less, such asabout 24.45 Angstroms or less, or about 24.40 Angstroms or less, orabout 24.35 Angstroms or less, such as about 24.30 Angstroms. In otheraspects, a variety of other types of molecular sieves can be used in ahydrocracking catalyst, such as zeolite Beta and ZSM-5. Still othertypes of suitable molecular sieves can include molecular sieves having10-member ring pore channels or 12-member ring pore channels. Examplesof molecular sieves having 10-member ring pore channels or 12-memberring pore channels include molecular sieves having zeolite frameworkstructures selected from MRE, MTT, EUO, AEL, AFO, SFF, STF, TON, OSI,ATO, GON, MTW, SFE, SSY, or VET.

In various embodiments, the conditions selected for hydrocracking candepend on the desired level of conversion, the level of contaminants inthe input feed to the hydrocracking stage, and potentially otherfactors.

Suitable hydrocracking conditions can include temperatures of about 450°F. (232° C.) to about 840° F. (449° C.), or about 450° F. (232° C.) toabout 800° F. (427° C.), or about 450° F. (249° C.) to 750° F. (399°C.), or about 500° F. (260° C.) to about 840° F. (449° C.), or about500° F. (260° C.) to about 800° F. (427° C.), or about 500° F. (260° C.)to about 750° F. (399° C.); hydrogen partial pressures of from about 250psig to about 5000 psig (1.8 MPag to 34.6 MPag); liquid hourly spacevelocities of from 0.05 h⁻¹ to 10 h⁻¹; and hydrogen treat gas rates offrom 35.6 m³/m³ to 1781 m³/m³ (200 SCF/B to 10,000 SCF/B). In otheraspects, the conditions can include temperatures in the range of about500° F. (260° C.) to about 815° F. (435° C.), or about 500° F. (260° C.)to about 750° F. (399° C.), or about 500° F. (260° C.) to about 700° C.(371° C.); hydrogen partial pressures of from about 500 psig to about3000 psig (3.5 MPag-20.9 MPag); liquid hourly space velocities of fromabout 0.2 to about 5 h⁻¹; and hydrogen treat gas rates of from about 213m³/m³ to about 1068 m³/m³ (1200 SCF/B to 6000 SCF/B).

In some aspects, portion of the hydrocracking catalyst can be containedin different reactor stages. In such aspects, a first reaction stage ofthe hydroprocessing reaction system can include one or morehydrotreating and/or hydrocracking catalysts. The conditions in thefirst reaction stage can be suitable for reducing the sulfur and/ornitrogen content of the feedstock. A separator can then be used inbetween the first and second stages of the reaction system to remove gasphase sulfur and nitrogen contaminants. One option for the separator isto simply perform a gas-liquid separation to remove contaminant. Anotheroption is to use a separator such as a flash separator that can performa separation at a higher temperature. Such a high temperature separatorcan be used, for example, to separate the feed into a portion boilingbelow a temperature cut point, such as about 350° F. (177° C.) or about400° F. (204° C.), and a portion boiling above the temperature cutpoint. In this type of separation, the naphtha boiling range portion ofthe effluent from the first reaction stage can also be removed, thusreducing the volume of effluent that is processed in the second or othersubsequent stages. Of course, any low boiling contaminants in theeffluent from the first stage would also be separated into the portionboiling below the temperature cut point. If sufficient contaminantremoval is performed in the first stage, the second stage can beoperated as a “sweet” or low contaminant stage.

Still another option can be to use a separator between the first andsecond stages of the hydroprocessing reaction system that can alsoperform at least a partial fractionation of the effluent from the firststage. In this type of aspect, the effluent from the firsthydroprocessing stage can be separated into at least a portion boilingbelow the distillate (such as diesel) fuel range, a portion boiling inthe distillate fuel range, and a portion boiling above the distillatefuel range. The distillate fuel range can be defined based on aconventional diesel boiling range, such as having a lower end cut pointtemperature of at least about 350° F. (177° C.) or at least about 400°F. (204° C.) to having an upper end cut point temperature of about 700°F. (371° C.) or less or 650° F. (343° C.) or less. Optionally, thedistillate fuel range can be extended to include additional kerosene,such as by selecting a lower end cut point temperature of at least about300° F. (149° C.).

In aspects where the inter-stage separator is also used to produce adistillate fuel fraction, the portion boiling below the distillate fuelfraction includes, naphtha boiling range molecules, light ends, andcontaminants such as H₂S. These different products can be separated fromeach other in any convenient manner. Similarly, one or more distillatefuel fractions can be formed, if desired, from the distillate boilingrange fraction. The portion boiling above the distillate fuel rangerepresents the potential lubricant base oils. In such aspects, theportion boiling above the distillate fuel range is subjected to furtherhydroprocessing in a second hydroprocessing stage for formation of oneor more lubricant base oils. Optionally, the lubricant base oilfractions can be distilled and operated in the catalyst dewaxingsections in a blocked operation where the conditions are adjusted tomaximize the yield and properties of each base oil.

Additional Configuration—Improved Lube Yield from Unconverted Oil

In some alternative aspects, a method is provided herein for improvingthe lubricant base oil yield when processing unconverted oil forlubricant production. Unconverted oil refers to the portion of a feedfor lubricant base oil production that is not “converted” relative to aconversion temperature, such as a 650° F.+(343° C.) portion or a 700°F.+(371° C.) portion, during a hydrotreating and/or hydrocrackingprocess. Such hydrotreating and/or hydrocracking processes can be usedto reduce the sulfur content of a feed as well as providing viscosityindex uplift. The unconverted oil after such hydrotreating and/orhydrocracking can have sufficient viscosity, as well as a suitableviscosity index, for formation of lubricant base stocks.

After hydrotreating and/or hydrocracking of a feed, the unconverted oilportion of the feed can be further processed by catalytic dewaxing. Thecatalytic dewaxing can be used to improve cold flow properties of alubricant base stock product, such as pour point. Typically, theunconverted oil can also be exposed to aromatic saturation conditionsbefore and/or after dewaxing. It is noted that aromatic saturation of adewaxed feed may alternatively be referred to as hydrofinishing of afeed. After dewaxing (and optionally after aromatic saturation), thedewaxed feed can be fractionated to form a plurality of desiredlubricant base stock products having different viscosities.

During dewaxing of unconverted oil to improve cold flow properties, thedewaxing conditions are typically selected to provide sufficient pourpoint improvement for the lubricant base stock product with the lowestpour point requirement (or multiple lower pour point products). This canoften correspond to the lowest viscosity base stock product, such as a 2cSt or less, or 3 cSt or less, or 4 cSt or less base stock product.These lower viscosity lubricant base stock products can require low pourpoints, such as −30° C. or lower, when they are targeted for use inspecialty applications such as transformer oils or refrigerator oils.Unfortunately, exposing an unconverted oil feed to sufficiently severedewaxing conditions to meet the pour point requirement for the lowestviscosity base stock product can result in reducing the pour point ofthe higher viscosity base stock products formed from the sameunconverted oil to pour points that are substantially beyond therequired pour point specification. This “overprocessing” of the higherviscosity portions of the unconverted oil can result in loss of inviscosity index for the higher viscosity lubricant base stocks. Tocompensate for the loss of viscosity index, additional hydrotreatmentand/or hydrocracking is typically used, which can provide viscosityindex uplift while reducing overall yield of lubricant base oilproducts.

In various aspects, to address the above difficulties, the unconvertedoil from hydrotreating and/or hydrocracking can be dewaxed at sufficientseverity for achieving the target pour points of the higher viscositybase stock fractions. The lowest (or optionally multiple lower)viscosity base stock fractions can then be stored and processed againover a dewaxing catalyst under effective conditions to meet theadditional cold flow property requirements for the lower viscosity basestock fractions.

FIGS. 4 and 5 schematically show the difference between wide cutprocessing of unconverted oil and the processing scheme describedherein. In FIGS. 4 and 5, an unconverted oil feed 110 is passed into ahydroprocessing stage 120 that represents both hydrotreatment anddewaxing. In the configuration shown in FIGS. 4 and 5, the effluent fromthe hydroprocessing stage 120 can be fractionated (not shown) to form alight base oil 132 (such as a 2 cSt oil), a medium base oil 134 (such asa 5-6 cSt oil), and a heavy base oil 136 (such as a 10+ cSt oil).

The configuration in FIG. 4 corresponds to the situation where theentire unconverted oil is dewaxed at a conventional increased severityto achieve the desired pour point for the 2 cSt light base oil 132. Tocompensate for this, the hydrotreatment portion of hydroprocessing stage120 is operated at higher severity as well, so that the viscosity indexof the medium base oil 134 and heavy base oil 136 will have a desiredvalue. In this prophetic example, the yields for the light base oil 132,medium base oil 134, and heavy base oil 136 are shown in FIG. 4 foroperation of the hydrotreatment and dewaxing processes at increasedseverity.

FIG. 5 demonstrates the yield benefit of operating the dewaxing stage220 at the lower severity effective conditions for satisfying the pourpoint for the medium base oil 234 and the heavy base oil 236. As shownin FIG. 5, because the light base oil 234 is not initially dewaxed to asufficiently low pour point, the light base oil 242 is recycled 245 forexposure to a dewaxing catalyst for a second time to produce anadditionally hydroprocessed light base oil 232. This results in a modestadditional reduction in yield for light base oil 232. However, theadditional loss in yield for light base oil 232 is small relative to thegains in yield for the medium base oil 234 and heavy base oil 236 due tothe lower severity hydrotreatment and dewaxing steps. As a result,processing according to the configuration shown in FIG. 5 can result ina net gain in overall lubricant base oil yield of several weightpercent, as shown by the difference in total yield of about 88 wt % forthe configuration in FIG. 4 versus about 94 wt % for the configurationin FIG. 5.

Additional Configuration—Improved Lube Yield from Unconverted Oil

In some alternative aspects, a method is provided herein for improvingthe lubricant base oil yield when processing unconverted oil forlubricant production. After hydrotreating and/or hydrocracking of afeed, a separation can be performed on the hydrotreated/hydrocrackedeffluent to form a roughly 150° C.+ fraction (alternatively a 125° C.+fraction or a 200° C.+ fraction) and a lower boiling fraction. The lowerboiling fraction can undergo further processing to separate out anaphtha boiling range portion from other light ends. The 150° C.+fraction, which included unconverted oil, can be passed into a dewaxing(and optionally hydrofinishing) stage for formation of one or more ofnaphtha boiling range products, jet fuel boiling range products, dieselboiling range products and lubricant boiling range products.

Unconverted oil refers to the portion of a feed for lubricant base oilproduction that is not “converted” relative to a conversion temperature,such as a 650° F.+(343° C.) portion or a 700° F.+(371° C.) portion,during a hydrotreating and/or hydrocracking process. Such hydrotreatingand/or hydrocracking processes can be used to reduce the sulfur contentof a feed as well as providing viscosity index uplift. The unconvertedoil after such hydrotreating and/or hydrocracking can have sufficientviscosity, as well as a suitable viscosity index, for formation oflubricant base stocks.

FIG. 6 shows an example of a process configuration for formation ofproducts from a vacuum gas oil boiling range feed. In FIG. 6, a vacuumgas oil boiling range feed 605 can be passed into a hydrocracker 620.The feed 610 can correspond to a virgin vacuum gas oil, a hydrotreatedvacuum gas oil boiling range feed, or another convenient type of feed.The hydrocracker 620 can correspond to a hydrocracker operating undersweet or sour conditions, depending on the nature of feed 610. Thehydrocracker effluent 625 can be passed into a stripper 630 (oralternatively another type of separator) for forming a 150° C.+ effluentfraction 635 and a lower boiling fraction 632. The 150° C.+ effluentfraction 635 can then be passed into a catalytic dewaxing stage 640.Optionally, the catalytic dewaxing stage can also include hydrofinishingcatalyst, or a separate reaction stage (not shown) can be used forhydrofinishing at any convenient location within the process flow. Thedewaxed effluent 645 can then be separated to form desired products. InFIG. 6, a first separation can correspond to an atmospheric distillation650 to separate out, for example, one or more naphtha boiling rangefractions 652, one or more jet fuel boiling range fractions 654, and abottoms fraction 655. In the configuration shown in FIG. 6, the bottomsfraction 655 then undergoes vacuum distillation 660 to form one or morediesel boiling range fractions 663, one or more lubricant boiling rangefractions. The lubricant boiling range fractions shown in FIG. 6correspond to a light lubricant fraction 667 and a heavy lubricantfraction 669, but any other convenient combination of fractions could beformed. Optionally, some or all of diesel boiling range fractions 663can be separated out by the atmospheric distillation 650.

ADDITIONAL EMBODIMENTS

Additionally or alternately, the present disclosure can include one ormore of the following embodiments.

Embodiment 1

A method of making a supported catalyst, the method comprising:impregnating a support comprising at least one of a zeolitic support anda mesoporous support with a Group VIII metal salt, the Group VIII metalcomprising Pd, Ni, Rh, Ir, Ru, Co, or a combination thereof, the GroupVIII metal optionally comprising a noble metal and preferably comprisingPd; calcining the support under first effective calcining conditions toform a Group VIII metal-impregnated catalyst; impregnating the GroupVIII metal-impregnated catalyst with a platinum salt; and calcining theGroup VIII metal-impregnated catalyst under second effective calciningconditions to form a platinum- and Group VIII metal-impregnatedcatalyst, wherein the platinum- and Group VIII metal-impregnatedcatalyst comprises a combined amount of platinum and Group VIII metal of0.1 wt %-5.0 wt % based on the weight of the catalyst.

Embodiment 2

The method of Embodiment 1, wherein the platinum- and Group VIIImetal-impregnated catalyst has a catalyst width and an average platinumcontent per volume, and wherein a peak platinum content per volumeacross the catalyst width differs from the average platinum content pervolume by less than 100% of the average platinum content per volume, orless than 75%, or less than 50%.

Embodiment 3

The method of any of the above embodiments, wherein the Group VIIImetal-impregnated catalyst comprises at least 0.1 wt % of Group VIIImetal, or at least 0.2 wt %.

Embodiment 4

The method of any of the above embodiments, wherein the first effectivecalcining conditions and/or the second effective calcining conditionscomprise calcining in an atmosphere containing 5 vol % to 30 vol % O₂ ata temperature of 500° F. (260° C.) to 800° F. (427° C.) for 0.5 hours to24 hours.

Embodiment 5

A supported catalyst comprising: a support comprising at least one of azeolitic support and a mesoporous support; and 0.1 wt % to 5.0 wt %,based on a weight of the supported catalyst, of a combined amount ofplatinum and a Group VIII metal, a weight ratio of platinum andpalladium being from 0.1 to 10, the Group VIII metal comprising Pd, Ni,Rh, Ir, Ru, Co, or a combination thereof, the Group VIII metaloptionally comprising a noble metal and preferably comprising Pd,wherein the supported catalyst has a catalyst width and an averageplatinum content per volume, and wherein a peak platinum content pervolume across the catalyst width differs from the average platinumcontent per volume by less than 100% of the average platinum content pervolume, or less than 75%, or less than 50%.

Embodiment 6

The supported catalyst of Embodiment 5, wherein the platinum and GroupVIII metal are impregnated on the support, the impregnation optionallybeing a sequential impregnation of Group VIII metal followed by platinumaccording to the method of Embodiment 1.

Embodiment 7

The method or supported catalyst of any of the above embodiments,wherein the support comprises a mesoporous M41S support, the supportoptionally comprising MCM-41.

Embodiment 8

The method or supported catalyst of any of the above embodiments,wherein the support comprises a molecular sieve having a zeoliteframework structure.

Embodiment 9

The method or supported catalyst of any of the above embodiments,wherein the platinum- and Group VIII metal-impregnated catalyst or thesupported catalyst comprises a combined amount of platinum and GroupVIII metal of 0.1 wt % to 2.0 wt %, or 0.2 wt % to 1.8 wt %, or 0.4 wt %to 1.5 wt %.

Embodiment 10

The method or supported catalyst of any of the above embodiments,wherein the platinum- and Group VIII metal-impregnated catalyst or thesupported catalyst comprises a platinum to Group VIII metal weight ratioof 0.1-2.0, optionally 0.2-1.0.

Embodiment 11

The method or supported catalyst of any of the above embodiments,wherein the platinum- and Group VIII metal-impregnated catalyst or thesupported catalyst has a catalyst width and an average combined platinumand Group VIII metal content per volume, and wherein a peak combinedplatinum and Group VIII metal content per volume across the catalystwidth differs from the average combined platinum and Group VIII metalcontent per volume by less than 100% of the average combined platinumand Group VIII metal content per volume, or less than 75%, or less than50%.

Embodiment 12

The method or supported catalyst of any of the above embodiments,wherein the support has an Alpha value of at least 100, or at least 200,or at least 250, or at least 300, or at least 350, or at least 400.

Embodiment 13

A method for hydroprocessing a feed, comprising: exposing a supportedcatalyst according to any of Embodiments 5-12 or a supported catalystmade according to any of Embodiments 1-4 or 7-12 to a feed having anaromatics content of at least 5 wt % under effective hydroprocessingconditions to form a hydroprocessed effluent.

Embodiment 14

The method of Embodiment 13, wherein the effective hydroprocessingconditions comprise at least one of aromatic saturation conditions,catalytic dewaxing conditions, and hydrocracking conditions, thehydroprocessed effluent optionally having a lower aromatics content thanthe feed.

Embodiment 15

The method of Embodiment 13 or 14, wherein the feed has an aromaticscontent of 5 wt % to 80 wt %, or at least 10 wt %, or at least 20 wt %,or at least 30 wt %, the feed optionally comprising a hydrocarbonaceousfeed.

EXAMPLES Examples 1-8: Aromatic Saturation Performance and Dispersion(Oxygen Chemisorption) for Various Catalysts

In this example, catalysts were formed by combining ZSM-48 with analumina binder in a 65:35 weight ratio. The combined ZSM-48 and aluminabinder was then extruded to form catalyst particles. The catalystparticles were then impregnated with Pt, Pd, or both Pt and Pd as shownin Table 1. Examples 1, 2, and 3 correspond to impregnation with eitherPt or Pd. Examples 4 and 7 correspond to co-impregnation of Pt and Pd.Examples 5, 6, and 8 correspond to sequential impregnation where adesired wt % of Pd was first impregnated onto the bound ZSM-48extrudate, followed by impregnation of the Pd-ZSM-48 catalyst with adesired amount of Pt.

The catalysts in Examples 1-8 were formed by impregnating the boundZSM-48 extrudates with tetramine metal complexes of Pt and/or Pd. Forsingle metal or co-impregnated catalysts, the metal impregnatedcatalysts were dried in still air for 4 hours followed by a calcinationin flowing air at 660° F. (350° C.) for 3 hours to decompose thetetraamine metal complexes after each impregnation to produce welldispersed platinum oxide, palladium oxide, or platinum and palladiumoxide alloy on the support surface. For the sequentially impregnatedcatalysts, the catalysts were produced by first impregnating the surfacewith the palladium complex followed by drying the catalyst in still airfor 4 hours and calcining in flowing air at 660° F. (350° C.) for 3hours to decompose the tetraamine metal complex and produce welldispersed palladium oxide. The resulting Pd-ZSM-48 catalyst was thenimpregnated with the platinum complex followed by drying the catalyst instill air for 4 hours and calcining in flowing air at 660° F. for 3 hourto decompose the tetraamine metal complex and produce platinum oxide.

TABLE 1 Catalyst Description Example Catalyst Description (All numberswt %) 1 0.6% Pt on 65% ZSM-48/35% Alumina 2 0.5% Pd on 65% ZSM-48/35%Alumina 3 0.9% Pd on 65% ZSM-48/35% Alumina 4 0.3% Pt-0.5% Pd on 65%ZSM-48/35% Alumina 5 0.3% Pt on 0.5% Pd on 65% ZSM-48/35% Alumina 6 0.5%Pt on 0.5% Pd on 65% ZSM-48/35% Alumina 7 0.3% Pt-0.9% Pd on 65%ZSM-48/35% Alumina 8 0.3% Pt on 0.9% Pd on 65% ZSM-48/35% Alumina

Table 2 shows two types of characterizations for the catalysts inTable 1. One type of characterization is an estimated dispersion, orfraction of noble metal surface area, as determined by the strongchemisorption of oxygen. The second characterization is the amount ofaromatics conversion under a specified test condition.

With regard to dispersion as measured by oxygen chemisorption, it isnoted that the amount of dispersion appeared to have a low correlationwith the amount of metals impregnated on the catalyst and a lowcorrelation with the resulting aromatics conversion under the aromaticsconversion test conditions. For example, Example 7 (co-impregnation)showed a substantially higher dispersion of metal than Example 8(sequential impregnation) at the same level of metals loading, butExample 8 had a substantially higher total aromatics conversion. Theexception was Example 1 (Pt only) which showed a low dispersion valueand a low total aromatics conversion value.

TABLE 2 Dispersion and Aromatics Conversion O₂ Chem. Total AromaticsExample (O/M) Conv. 1 0.52 24.1% ± 0.8% 2 0.92 58.2% ± 1.3% 3 0.57 62.3%± 0.5% 4 0.74 56.8% ± 0.3% 5 0.67 64.4% ± 0.1% 6 0.73 66.3% ± 0.2% 70.65 61.4% ± 0.4% 8 0.46 72.5% ± 0.2%

For the aromatics conversion percentage shown in Table 2, theperformance of each catalyst for aromatic hydrocarbon saturation(hydrogenation) was determined on a hydrotreated 600 N dewaxed oil. Thedewaxed oil was previously hydrotreated to reduce the sulfur content toapproximately 70 wppm to be representative of a typical feed forlubricant base stock production prior to dewaxing. Approximately 0.08 gof catalyst sized to a 50/170 mesh was loaded into a batch reactor.After pressure testing with nitrogen, the catalysts were dried innitrogen at 150° C. for 2 hours followed by reduction in 250 psig (1.7MPa) H₂ at 300° C. for 2 hours. The reactor was then cooled to roomtemperature and transferred to a glove box under a blanket of nitrogen.After opening the reactor under a blanket of nitrogen, approximately 3cc of dewaxed oil was introduced to the batch reactor and the reactorwas resealed. The aromatic saturation activity test was then conductedfor 12 hours at 250° C. with 900 psig (6.2 MPa) of H₂.

The total aromatics were measured by UV absorption (mmol kg⁻¹). Thepercentage of total aromatics converted are shown in Table 2. Thearomatic saturation experiments were run in quadruplicate to determine astandard deviation on the conversion and show statistical significance.At two different weight loadings (Example 5: 0.3% wt Pt-0.5 wt % Pd andExample 8: 0.3 wt % Pt-0.9 wt % Pd), the sequentially impregnatedcatalysts showed substantially improved aromatic saturation performancecompared to co-impregnated catalysts (Examples 4 and 7) with the samenoble metal loading. The addition of 0.5 wt % Pt on 0.5 wt % Pd (Example6) instead of 0.3 wt % Pt on 0.5 wt % Pd (Example 5) showed only amodest further increase in the aromatic saturation activity of thecatalyst. The co-impregnation of Pt and Pd (Examples 4 and 7) on thesupport appeared to have more similarity in aromatic saturation activitywith the samples having only the same amount of Pd (Examples 2 and 3).The Pt only catalysts appeared to be significantly lower in totalaromatics activity than the other catalysts.

The results in Table 2 show that the three highest aromatic saturationactivities were achieved using sequential impregnation of Pd followed byPt (Examples 5, 6, and 8). This is in spite of Example 7 having a highertotal metals loading that Example 5 or 6. This demonstrates theunexpected benefit of using sequential impregnation of Pd followed by Ptfor improving aromatic saturation activity.

Example 9—Aromatic Saturation Catalyst Characterization

The benefit of sequential impregnation of platinum and palladium wasalso investigated for an aromatic saturation-type catalyst. A supportcontaining 65 wt % MCM-41 and 35 wt % alumina was co-impregnated andsequentially impregnated with platinum and palladium tetraamine nitratesin similar manners to the procedures described above for examples 1-8. Aco-impregnated 0.15 wt % Pt and 0.45 wt % Pd on MCM-41 support andsequentially impregnated 0.15 wt % Pt on 0.45 wt % Pd on MCM-41 supportwere evaluated for aromatic saturation performance for hydrofinishing a600N dewaxed oil. Approximately 5 cc of each catalyst was loaded into anupflow micro-reactor. About 3 cc of 80-120 mesh sand was added to thecatalyst to ensure uniform liquid flow. After pressure testing withnitrogen and hydrogen, the catalysts were dried in nitrogen at 260° C.for about 3 hours, cooled to room temperature, activated in hydrogen atabout 260° C. for 8 hours and cooled to 150° C. Then feed was introducedand the operating conditions were adjusted to 2.0 hr⁻¹ LHSV, 1000 psig(6.9 MPa), and 2500 scf/b (425 m³/m³). The reactor temperature wasincreased to 275° C. and then held constant for about 7-10 days.Hydrogen purity was 100% and no gas recycle was used.

FIG. 1 shows results from the aromatic saturation tests on the 600 Nfeed. As shown in FIG. 1, the sequentially impregnated catalyst(triangle data points) produced an effluent with a substantially loweraromatics content than the co-impregnated catalyst. This furtherdemonstrates the unexpected benefit of using sequential impregnation ofPd followed by Pt for aromatic saturation activity.

Examples 10 and 11—EDS Characterization

Table 2 appears to demonstrate that sequential impregnation can be usedto provide improved aromatics saturation activity. Table 2 also showsthat conventional dispersion measurements, such as oxygen chemisorption,cannot distinguish between catalysts with reduced and improved aromaticssaturation activity. It has been determined that the differences inaromatic saturation activity for sequentially impregnated catalysts canbe characterized at least in part by using energy dispersive x-rayspectroscopy (EDS) analysis using a scanning electron microscope (SEM).EDS can allow for characterization of the metal distribution across thewidth of a catalyst.

FIG. 2 shows an EDS characterization of the distribution of Pt and Pdmetal content across the width of alumina bound ZSM-48 (65:35 weightratio) for a co-impregnated catalyst. FIG. 3 shows an EDScharacterization for a similar catalyst that was formed using sequentialimpregnation. In FIGS. 2 and 3, the displayed values for each metal arenormalized so that the maximum concentration at a given widthcorresponds to a value of “1”. As shown in FIG. 2, both the Pd and Ptcontents show increases in metal content near the edges of the catalystwidth, which is believed to correspond to increased metal content at thecatalyst surface. It is noted that both the Pd and Pt have similardistribution profiles. By contrast, FIG. 3 shows a relatively uniformdistribution of both Pd and Pt throughout the width of the catalyst.This is believed to indicate that Pd and Pt are distributed more evenlywithin the pore network of the catalyst in FIG. 3, as opposed to havingmetals concentrated at the surface for the catalyst in FIG. 2.

When numerical lower limits and numerical upper limits are listedherein, ranges from any lower limit to any upper limit are contemplated.While the illustrative embodiments of the invention have been describedwith particularity, it will be understood that various othermodifications will be apparent to and can be readily made by thoseskilled in the art without departing from the spirit and scope of theinvention. Accordingly, it is not intended that the scope of the claimsappended hereto be limited to the examples and descriptions set forthherein but rather that the claims be construed as encompassing all thefeatures of patentable novelty which reside in the present invention,including all features which would be treated as equivalents thereof bythose skilled in the art to which the invention pertains.

The invention claimed is:
 1. A method for processing a feed using asupported catalyst, comprising: exposing a feed having an aromaticscontent of at least 5 wt % to a supported catalyst under effectivearomatic saturation conditions to form an effluent, the supportedcatalyst comprising: a support comprising at least one of a zeoliticsupport and a mesoporous support, the support having an Alpha value ofat least 100; and 0.1 wt % to 5.0 wt %, based on a weight of thesupported catalyst, of a combined amount of platinum and Group VIIImetal on the support, a weight ratio of platinum to Group VIII metalbeing from 0.1 to 10, the Group VIII metal comprising Pd, Ni, Rh, Ir,Ru, Co, or a combination thereof, wherein the supported catalyst has acatalyst width and an average platinum content per volume, and wherein apeak platinum content per volume across the catalyst width differs fromthe average platinum content per volume by less than 100% of the averageplatinum content per volume.
 2. The method of claim 1, wherein theeffluent has a lower aromatics content than the feed.
 3. The method ofclaim 1, wherein the feed has an aromatics content of 10 wt % to 80 wt%.
 4. The method of claim 1, wherein the platinum and Group VIII metalare impregnated on the support, the impregnation comprising:impregnating the support with a Group VIII metal salt; calcining thesupport under first effective calcining conditions to form a Group VIIImetal-impregnated catalyst; impregnating the Group VIIImetal-impregnated catalyst with a platinum salt; and calcining the GroupVIII metal-impregnated catalyst under second effective calciningconditions to form a platinum- and Group VIII metal-impregnatedcatalyst.
 5. The method of claim 1, wherein the platinum comprises aplatinum oxide and the Group VIII metal comprises a Group VIII metaloxide.
 6. The method of claim 5, wherein the Group VIII metal oxidecomprises palladium oxide.
 7. The method of claim 1, wherein the supportcomprises ZSM-48.
 8. The method of claim 1, wherein the Group VIII metalis palladium.
 9. The method of claim 1, wherein the weight ratio ofplatinum to Group VIII metal is from 0.1 to
 2. 10. The method of claim1, wherein the support comprises a mesoporous M41S support.
 11. A methodfor processing a feed using a supported catalyst, comprising: exposing afeed having an aromatics content of at least 5 wt % to a supportedcatalyst under effective aromatic saturation conditions to form aneffluent, the supported catalyst comprising: a support comprising atleast one of a zeolitic support and a mesoporous support, the supporthaving an Alpha value of at least 100, and comprising a 10-member ringin a crystal structure thereof; and 0.1 wt % to 5.0 wt %, based on aweight of the supported catalyst, of a combined amount of platinum andGroup VIII metal on the support, a weight ratio of platinum to GroupVIII metal being from 0.1 to 10, the Group VIII metal comprising Pd, Ni,Rh, Ir, Ru, Co, or a combination thereof, wherein the supported catalysthas a catalyst width and an average platinum content per volume, andwherein a peak platinum content per volume across the catalyst widthdiffers from the average platinum content per volume by less than 100%of the average platinum content per volume.
 12. The method of claim 11,wherein the platinum comprises a platinum oxide and the Group VIII metalcomprises a Group VIII metal oxide.
 13. The method of claim 12, whereinthe Group VIII metal oxide comprises palladium oxide.
 14. The method ofclaim 11, wherein the support comprises ZSM-48.
 15. The method of claim11, wherein the platinum and Group VIII metal are impregnated on thesupport, the impregnation comprising: impregnating the support with aGroup VIII metal salt; calcining the support under first effectivecalcining conditions to form a Group VIII metal-impregnated catalyst;impregnating the Group VIII metal-impregnated catalyst with a platinumsalt; and calcining the Group VIII metal-impregnated catalyst undersecond effective calcining conditions to form a platinum- and Group VIIImetal-impregnated catalyst.
 16. The method of claim 11, wherein theGroup VIII metal is palladium.
 17. The method of claim 11, wherein thesupport comprises a mesoporous M41S support.
 18. A method for processinga feed using a supported catalyst, comprising: exposing a feed having anaromatics content of at least 5 wt % to a supported catalyst undereffective aromatic saturation conditions to form an effluent, thesupported catalyst comprising: a support comprising at least one of azeolitic support and a mesoporous support, the support having an Alphavalue of at least 100; and 0.1 wt % to 5.0 wt %, based on a weight ofthe supported catalyst, of a combined amount of platinum and Group VIIImetal on the support, a weight ratio of platinum to Group VIII metalbeing from 0.1 to 10, the Group VIII metal comprising Pd, Ni, Rh, Ir,Ru, Co, or a combination thereof, the platinum comprising platinumoxide, and the Group VIII metal comprising a Group VIII metal oxide,wherein the supported catalyst has a catalyst width and an averageplatinum content per volume, and wherein a peak platinum content pervolume across the catalyst width differs from the average platinumcontent per volume by less than 100% of the average platinum content pervolume.
 19. The method of claim 18, wherein the Group VIII metal ispalladium.
 20. The method of claim 18, wherein the weight ratio ofplatinum to Group VIII metal is from 0.1 to 2.